Telegraphic photography.



. C. STILLB.

TELEGRAPHIG PHOTOGRAPHY. APPLIOATIONIILEDMARA,1912- 1 1 1 6,949, Patented Nov. 10; 1914.

2 SHEETS-SHEET 1.

[nveniar I A21 )f'iiarna C. STILLE.

TELEGRAPHIG PHOTOGRAPHY.

APPLICATION FILED MAR.4, 1912.

Patented NOV. 10, 1914.

2 SHEETS-SHEET 2.

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UNITED STATES: ATENT OFFICE.

cum srnmn, or rmnnnnnv, Nana mrlnm, enemy.

TELEGZ BALPHIC PHOTOGRAPHY;

Speciflcationofletters meat. Patented Nov.10,1914.

V Applioatlonilledflarch4,1912. Serial m. 681,553.

To all whom it may concern: I

.Be it known that I, CURT STILLE, doctorof philosophykof Friedenau, near Berlin, a

sllb ect of the ing of Prussia, German Empire, have invented 'certam new and useful Improvements in Telegraphic Photography; and I do herebydeclare the followlng to be a full and clear and exact description of the same reference being had tothe accompanymg drawings, forming a part of the specification.

My invention relates to telegraphic pho tography and more particularly to a system by which the electric and the 0 111ml 0 erations are done separately in di erent p aces.

In the system for telegraphic transmis- -sion of photographs it is usual to combine the optical and electrical operations in one apparatus. Evidently this manner of operation has serious draw-backs and disadvantages. The operator must be skilled in the optical as well as in the electrical operations so that an ordinary telegraphist is not able to perform all the operations. Moreover, as usually, the photographic ex osure and the electric transmission are com ined, the telegraphic line is occupied for a considerable time. This evidently causes expenses which do not allow the practical use of telegraphic According to my invention the photographic exposure is done separately, and the apparatus used for it is of such a nature that it produces a wire magnetized corresponding to the photograph as will be seen afterward.

This apparatus will be called in the 01- lowing the o tical receiving station. The

magnetized w1re will then be removed from the optical receiving station and may be I brought to the telegraphic transmitting station.

The apparatus used in the electric transmitting station is of a similar nature as the well known'apparatus of Poulsen for transmitting speech telephonically, thateis to say in this station a wire is made to pass before the poles of an electro-magnet, in which it induces current strength corresponding to the variations of magnetism in the magnetized .wire. These currents are transmitted by a line to the third station, viz., the electric receiving station. -In this station the induced currents traverse an induction coil. with the magnetic core. The magnetism ex-' cited in the pole of the core is transmitted to a w1re running near the face of the pole.

{The' result is a second magnetized wire :whose magnetlsm corresponds to the magnetism of the first wire, each variation being exactly reproduced. Now the magnetized wire may he removed from the third station,

that is to say from the electric receiving station, and brou ht to the optical ram forming station w ich "transforms thej vari-l atlons of magnetism into variations of 'light It is evidentthat by the new system two advantages are arrived atviz:' 1.; The opy any of the known methods as will he afterward described. a

tical operations are absolutely separated from the electrical ones so that in the telegraphic station the ordinary telegraphist will be able to accomplish the service. 2. The second advantage isv that the magnetized wire can be made to run before. the poles of the electro-magnets with a speed which is independent of the optical operaitions. It may run at a very high speed with former used in the electrical receiving station. Fig. 5 shows a device used for the optical and photographical exposure.

With reference to Fig. 1 A means the optical and photographical receiving station. A photographic camera a is used mstead of t e ordinary screen of mat glass. A photo-electriccell b is arranged at the rear end of the camera. Before the photographic cell a flat band is arranged which is able to run before the cell. This band which .is illustrated in Fig. 2, has a series of holes'a'rranged in certain distances correspondin to the breadth of the photo-electric cell. he holes are arranged in diflerent heights, he length of the heights being chosen acc'or mg to the conditions of the case. The band is opaque with the exception of the holes.

Now if we assume the band to run from the right to the left the light will penetrate through the holes a, w, m w, w", &c. The image which is assumed in the drawing to be a church will cause in every instance a small spot of light which corresponds to a spot of the image.

In the drawing the hole a: has passed the picture, in the hole :12 it being nearto the tower of the church. Evidently the light received in every moment by the photo-electric cell will correspond to the instantaneous intensity of brightness of the image, and the whole image Wlll be divided into strips, the number of which is equal to the number of the holes.

The photo-electric cell is a galvanic element inclosed in a vessel of glass and having as electrodes two plates of silver which dip into an aqueous sulfuric acid. The plate which is opposite to the interior of the camera is covered with halogen salt of silver (chlorin, iodin, bromin). The cell of the plate which is opposite to the camera is ground lain to avoid an disturbances for the passing image. Thep oto-electric cell is, as stated, inclosed in a vessel of glass and the walls of this vessel must be two parallel Elanes, in order to avoid any disturbing inuence of refraction, as would be the case with the walls of the ordinary glass vessel.

Experiments have shown that a surface of 2.2 inches is suflicient for the electrodes of the fell1 to produce satisfying differences of 1g t.

By the action of light an electromotive force is generated, which is proportional to the intensity of light. The two poles of the photo-electric cell are connected to the primary coil p of a telephonic relay 0 having the secondary coil 8.

In the circuit of the secondary s a battery and an electro-magnet e are connected. The object of the relay is to magnify the intensity of the currents which would be too weak to be used directly. The currents induce magnetism in the core of the -electro= magnetic coil e, which as it will be seen is such that the instantaneous intensity of magnetism corresponds exactly to the instantaneous intensity of the light of the illuminated spot in the camera.

Underneath the core runs a wire of steel dsuitably arran ed. Ona frame are two drums t t whic may be driven mechanically, so that the wire is wound on one of the drums and unwound from the other running over the rollers r. 1'

Experiments have shown that a speed of 2 to 3 yards per second will give satisfactory results.

After the wire is magnetized its magnetism corresponding, as having been said, to the variation of the intensity of light in the image it may be removed from the drums and brought to the transmitting station forming a part of the electric station B. The wire is made to pass before the pole of the electro-magnet e (on the left side of the figure running from drum t) over the rollers r 1" to drum 6 Now the magnetism will produce-in the core a new magnetism corresponding exactly to the magnetism of the wire. The magnetism of the core in the coil e will induce currents which are transmitted to the relay 0 and from thence to the line f f. In the circuit of this line is connected an electromagnet coil e of similar nature as described, and before the ole of its core runs a wire (1 to be magnetlzed in analogous manner to thewire already magnetized. This wire may now be removed from the electric receiving station and brought to the optical transmitting station. In this station a similar reproduction will be effected. The wire runs from drum t over the rollers 'r' r to drum 25", before the pole of the electromagnet e and produces variation of currents in the primary coil p of the transformer whose object is to transform the electric variations into optical ones.

The transformer is shown'in Fig. 4. Its core is a tube of glass being sealed at the top and at the bottom lgy two Nicol prisms, the tube being filled with carbonic disulfite or similarly acting liquids. Around the tube is a layer lc of finely divided iron, for instance iron chemically deposited. For increasing a magnetic action in the circuit of the secondary s a battery may be connected. Now by well known laws a beam of light passing through the Nicol prism and the solution of carbonic disulfite will be polarized so that its intensity of light is proportional to the current which traverses the coil. The be m may be used to act on a moving photographic plate, the movement corresponding to the movement of the band 0 of Fig. 1, i. e. the picture moving in such a manner that a series of strips of light are produced on the plate w. Instead of the optical transmission as described any other of the well known methods to convert an electric cur-' rent whose intensit corresponds to the intensity of a spot of a picture may be used. One of those systems is known under the name of Korn.

I do not limit myself to the details of the specification as the means used may be changed, but I consider as new and essential for my invention the division of the electric optical station in a broad sense.

What I do claim as my invention and desire to secure by Letters Patent of the United States, is-

1. A method of photo-electric telegraphy consisting in converting the variations of intensity of light into variations of intensity of electric current and recording such variations of current as variations in the strength of magnetism, reproducin the magnetism in electric currents and t e electrical currents in variations of magnetism and converting the variations of magnetism into variations of intensity of light.

2. A method of photo-electric telegraphy consisting in converting the variations of intensity of light into variations of intensity of electric current and recording such variations of current as variations in the stren h of magnetism, reproducin the magnetism in electric currents and t e electrical currents in variations of magnetism and converting the variations of magnetism into variatlons in intensity of electric current and converting the variation in intensity of said last mentioned electric current into a variation of light.

3. A method of photo-electric telegraphy consisting in converting the variations of intensity of light into variations of intensity of electric current and recording such variations of current as variations in' the stren of magnetism, reproducin the magnetism in electric currents and t e electrical currents in variations of magnetism and converting the variations of magnetism into variations in intensity of electrical current and causing the variations of the last mentioned electrical current to magnetically act on a body having magnetical optical rotary power.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

CURT STILLE. Witnesses:

Woman-m Ham, HENRY Hasrmz. 

